Alloying of gray iron in the cupola



Patented Aug. 9, 1949 ALLOYING OF GRAY IRON IN THE CUPOLA Calbert L. Vance, Columbus, Ohio, assignor to Ohio-Ferro Alloys Cor a corporation of Ohio poration, Canton, Ohio,

No Drawing. Application December 29, 1945, Serial No. 638,479

Claims. (CI. 7544) 1 The invention relates to ferro alloy or metal briquettes for use as additions to the cupola charge for making gray iron, as well as the manufacture of such briquettes and the present application is a continuation in part of my pending application for Ferro alloy briquette and manufacture of same, Serial No. 513,953, filed December 11, 1943, now Patent No. 2,405,278.

It is customary in the manufacture of gray iron I to make additions of various metals or ferro alloys such as chromium, silicon, manganese, copper, nickel, molybdenum, phosphorus, and the like to the cupola charge.

In order to produce the desired results it is necessary that a definite quantity of the desired metal product or ferro alloy be added to the charge or melt and it is therefore necessary that each piece or lump of the metal or ferroalloy addition will have a definite metallic content.

To this end it has long been common practice to form briquettes of a definite known weight of the desired metal or ferro alloy, in finely divided form, mixed with a binder such as Portland cement, clay, lime or similar material.

The use of pitch, tar, or a mixture thereof, as a binder in the production of briquettes of various materials is not new, but to the best of my knowledge neither of these materials has ever been actually used as a binder for briquettes of metals or ferro alloys that are subjected to temperatures higher than the melting or fusion point of the pitch or tar, and it has been generally believed by the steel industry that pitch or tar do not form suitable binding agents for such use be cause of the erroneous belief that they would immediately burn away in the furnace permitting the briquettes to disintegrate and exposing the readily oxidizable alloys to the oxidizing flames of the furnace so that they are lost in whole or at least in part.

As an example of the erroneous belief that pitch or tar is not a suitable binder for ferro alloy briquettes attention is called to Greiner Patent No. 1,551,554 of September 1, 1925, for a Process.

for smelting iron alloys.

It is therefore the object of the present invention to provide a briquette for cupola additions composed of one or more ferro alloys or metals in finely divided condition bound together by pitch or tar or a mixture thereof.

Another object is the formation of a briquette of such metalliferous products bound together with pitch or tar under extreme pressure.

A still further object is to provide a method of producing a briquette of this character by mixing ferro alloy material with a small amount of hot pitch or tar and'subjecting the same to a suitable pressure toform a brlquette.

A further object of the invention is to provide a briquette of ferro alloys or metals that when added to the cupola charge will melt and alloy with the charge to which it is added and not lag behind in the cupola and become part of the following charge or charges as is the case with some briquettes.

' The above objects, together with others apparent to those skilled in the art, or which may be later referred to, may be attained by carrying out the invention in the manner hereinafter described in detail.

In carrying out the invention to produce the briquettes from any desired ferroalloy such as silicon, manganese, chromium, phosphorus, or the like, the desired alloy or alloys may be in small pieces, or in finely divided condition, or a mixture of the two. To this I add a small, usually about 3 to 5 per cent ;by weight of pitch or tar or a mixture of the two, preferably having a high melting point, and preferably hot.

'Tl'ie ferroalloy and binder are intermixed and may be placed in a mold of suitable size and shape to produce the briquette desired and subjected to extreme pressure, preferably about two tons per square inch or the briquette may be formed in an extruding press with less pressure.

Actual commercial tests of the ferro alloy briquettes described herein were made under varying conditions to determine the silicon recovery as compared to the silicon recovery from standard silvery iron. These tests are as follows:

EXAMPLE 1 Cupola 72", using lI-ounce pressure; operation eight hours with a continuous stream of metal from the cupola. The test covers three days operation and on the second day ferro silicon briquettes were substituted for silvery iron on the basis of contained silicon.

Regular charge BRIQUE TTE IRON CHARGE 1,050 lbs. Steel scrap, 0.147 Si Si 100 lbs. Plg 117011 2.55% 6S1 2.55 lbS. S1 3 lsgriquelttes (0141A; g S I 21 150 lbs Return scrap 1. 0% Si 2.40 lbs. Si 40 Piege "01111-23 o l 380 lbs. R turn so a 1.50 S 5.70 lbs. S1

735 lbs. Purchasedscrap 1.70% s1 12.50lbs.S1 5 e 1 lbs, Silvery iron 15.75% s1 2.36 lbs. s1 1,5901bs- Total 21-611bs-S1 S1 1. 52% s1 1,000 lbs. 19.81 lbs. Si

1.98% Si N Analysis Brzquette charge 10 Test No. s1 Charge ohares 100 lbs. Pig iron 2.55% Si 2.55 lbs. s1 V g C S P M11 150 lbs. Return serap 1.60% Si 2'-'.40lbs. Si S1 Y 3 17', 84 745 Purchased Scrap 110% 1513535105: 19 3:11 1151 11110 1300' .84 Si 12.67 lbs. S1 S flyery 3g 3.0; 1.21 .074 .099 .09 5.5 lbs. Briquettes 46.5% s1 2.55 lbsSi i M f ff f 9 1,000.5 lbs. 20.17 lbs. Si

210I%' .S1 I Test No.-- ;i Transverse Deflection Per cent silicon in ladle metal I 1 I I e 10 .011 0 Regular 'Brlquette R gnlar Tune of Test- ,000 2835 .279 Charge Charge arge 50,890 3605 391 1.80 1.88 1.83 1.70 I 1.81 1.74 EXAMPLE 4 r f g: 0111:1010 48",blastpresslire'l2'ouiicesl] 1283 1.80 1.03

Charge Pitcli 1101011111015, 3? EXAMPLE 2 1 Pounds Cupola melting 16' tonsper hour made four 1 test runs as follows:- Test A and C with sil- 353 .f, 5 ;1 9 1 25-00 very iron and B and D replacing silvery iron .90 1 2813 13:20 20:3 with ferro-silicon briquettes as described above. 75 1:5 Two types of iron were made each day and the 20 10.00 charges used were as follows: 25000. I 64.3.

Soft 1 I Iron Pounds Regular Pounds 7 charge other briquettes S Mlxlbs' I 40;- [Same'oharge as-above ior pitch briquettes-J Silnery Iron I Other Briquettes- Besserner gig ((S i7=2).45%)' 1 82(5) I I Returns( i2.l 0 .1 V 7 2. cirper Si er 0. SteelScrap ($10157 15 0:10 425' 0. 03- v P Silvery P1g(s11o.47 80 8.38 80- ass F V i cent Total -..2;500 61-128 2:500 5-1 51 Etc-name 2:85 2.234 SiliconBriquettek' 2nd Charge I Bessemer Pig (Si2A57) 1,025 25.10 1025 25.10- 1 Returns s12.10% 1 ,392: 29.20 11042 21.90- Steel Scrap 425 010?" 2 20'- 0 40- 2 75 1 22 Silicon (in briquotte iorm). 8 8.00 V 8.00:

Total 2, 500 02.41 2500 55.60 9

' The above tests prove that recovery of silicon Analysis of heats Test A 1 B c 1) Sample Number #1 #2 #1 #2 #1 #2 I #1 #2 Silicon percent." 2132 1. 71 2.212 1.88 2.31 1,90 2.37 2.0 T0101 .a'rbon. 3100 3.3a 3.55 3.39 3.511 3.41 3.115 I 3.55- Tensile, p. s.i 22,930 30,090 25,950 29,710 23;?380 29,800 11,550; 29:850 Transverse... 3,500 4,300 3,480 4,090 3,920 4,070 2,920 4,270 Defleotionfln) .188 .183 .19 .183 .192 .200 .1 .1 79 Brinnel 149 197 103 1 79 150 179 1:17 137 C 1 I m t EXAM? E 3 from the product made according to this invenupo 0.48 as pressure Jounees, 1 2.8lbs. sieddedperteninthe1e 11e=.12%......-... .12% 9 ys g s i m m? fi g e for fer SILVERY IRON- CHARGE 0- es rique e or use e cupo a.

70 I claim:

1,050 lbs. Steel scrap, 14% Si' .1.

051m. Silvery iron, 15.75% S 401bs. Spiegel iron, 1.23% Si .49'lbs 3l5lbs. Return scrap, 1.50% Si 4. 73 lbs.

1, 500 lbs. Total 2'1. 05 lbs. s1 1. 45%s1 117% Si 73; the mixture intohighly compressed. briquefites,

adding the briquettes to the cupola charge and melting the charge in the cupola to produce alloyed gray iron.

2. The method of alloying gray iron in the cupola which consists in mixing only ferro alloy fragments and about 5% of a binder taken from a group consisting of hot tar and pitch and forming the mixture into highly compressed briquettes, adding the briquettes to the cupola charge and melting the charge in the cupola to produce alloyed gray iron.

3. The method of alloying gray iron in the cupola which consists in mixing only ferro-alloy fragments and about 5% of a binder consisting of hot, high melting point tar and forming the mixture into highly compressed briquettes, charging the briquettes with pig iron and scrap into the cupola and melting the charge in the cupola to produce alloyed gray iron.

4. The method of alloying gray iron in the cupola which consists in mixing only ferro-alloy fragments and about 5% of a binder consisting of hot, high melting point pitch and forming the mixture into highly compressed briquettes, charging the briquettes with pig iron and scrap into REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,551,554 Greiner Sept. 1, 1925 FOREIGN PATENTS Number Country Date 157,947 Great Britain Jan. 10, 1921 

